Page 299 - Handbook of Energy Engineering Calculations

produced by coal-fired plants. Crop- and crop-residue-fired plants could
eventually supply some 10 percent of the electrical energy needed by the
midwestern states.
Current cost to produce a kilowatt of electricity using wind power is less
than 6 cents. This compares favorably with the 4–6 cents cost per kilowatt for

the typical coal-fired generating station. When the relatively low cost of wind
power is combined with its nonpolluting features, this form of electrical
generation is extremely attractive to environmentally conscious engineers and

scientists.
The advantages cited above apply equally well to many other nations
throughout the world. In some areas wind power offers a simple, low-cost
solution to energy needs without resorting to complex technical methods.
Wind power does have a worldwide future.

The illustrations and much of the data in this procedure are the work of
Fritz Hirschfeld, as reported in Mechanical Engineering magazine. Also
reported in the magazine is a proposal by J. S. Goela of Physical Sciences,

Inc., to use kites to extract energy from the wind.
Kites avoid the use of high-capital-cost components such as windmill
towers and large rotors. Further, a kite can utilize the full available potential
of the wind. As Fig. 7 shows, the earth’s boundary layer extends up to 5000 ft
(1500 m) above sea level. In this boundary layer, the average wind velocity

increases while the air density decreases with altitude. Consequently, the total
3
available wind power per unit area (= ½ ρV ) increases with altitude until at
an altitude of 5000 ft (1500 m) a maximum is reached. The ratio of available

wind power in New England at 5000 ft (1500 m) and 150 ft [many wind
systems operate at an altitude of 150 ft (50 m) or less] is 25. This is a large
factor which makes it very attractive to employ systems that use an energy
extraction device located at an altitude of 5000 ft (1500 m). Even at an

altitude of 1000 ft (300 m), this ratio is large, approximately equal to 10.